The present invention relates generally to methods and apparatus for grasping and moving workpieces. More particularly, the present invention relates to methods and apparatus for grasping and/or moving workpieces which are sensitive to contamination and/or fragile.
Today, many products are produced inexpensively and in high volume using highly mechanized and/or automated manufacturing techniques. Examples of workpieces which are sometimes handled using mechanized and/or automated equipment include transparent glass panes, glass mirrors, and semiconductors (e.g., wafers, chips, and dies). When practicing such manufacturing techniques, it is often necessary for a machine to grasp and move a workpiece. This may be accomplished using some sort of gripper.
In some cases, the material of the gripper may leave residue on the workpiece. Additionally, relative movement between the gripper and the workpeice (e.g., rubbing) may cause damage to the workpiece in some cases. Thus, it is desirable to efficiently grasp and transfer workpieces while at the same time minimizing contamination of the workpiece and damage to the workpiece.
The present invention relates generally to methods and apparatus for grasping and moving workpieces. More particularly, the present invention relates to methods and apparatus for grasping and/or moving workpieces which are sensitive to contamination and/or fragile. An assembly in accordance with an exemplary implementation of the present invention includes a disk and a cup shaped member having a mid portion fixed to a central portion of the disk. A skirt of the cup shaped member may be advantageously dimensioned to urge an outer portion of the disk out of plane with a central portion of the disk so that the disk defines a cavity when the skirt is disposed in a resting shape. The skirt may also advantageously have a level a resilience selected to allow the skirt to assume a stretched shape while the disk is assuming a generally planar condition.
In one aspect of the present invention, the disk is interposed between the cup shaped member and a workpiece. Accordingly, in some implementations, the disk advantageously prevents the cup shaped member from contacting the workpiece. Additionally, the disk may advantageously prevent the skirt of the cup shaped member from rubbing on the workpiece, for example, when skirt stretches to assume a stretched shape.
A method of moving a workpiece in accordance with an exemplary implementation of the present invention comprises the steps of providing a disk having a generally planar condition and urging an outer portion of the disk out of plane with a central portion of the disk so that the disk defines a cavity. A source of relatively low pressure is placed in fluid communication with the cavity defined by the disk and the disk is positioned against a workpiece. The workpiece may be moved, for example, by moving the disk while the disk is positioned against the workpiece.
In some advantageous implementations of the present invention, the disk is adapted to move between a planar condition and a folded condition by folding and unfolding without significant stretching and unstretching. More particularly, the length of an edge of the disk preferably remains substantially unchanged as the disk moves between a planar condition and a folded condition. A disk which moves between a planar condition and a folded condition by folding and unfolding without significant stretching and unstretching may conform to the face of a generally planar workpiece with minimal rubbing between the disk and the workpiece.
In some advantageous implementations of the present invention, the skirt of the cup shaped member comprises an elastomeric material and the disk comprises a non-elastomeric material. When this is the case, the elastomeric material forming the skirt may allow the skirt to assume a stretched shape. Also in these advantageous implementations, the nonelastomeric material forming the disk may allow the disk to move between a planar condition and a folded condition by folding and unfolding without significant stretching and unstretching of the material forming disk.
A disk assembly in accordance with an exemplary implementation of the present invention may include a disk having a first surface and an annular ring of adhesive disposed on the first surface of the disk. An inner extent of the adhesive and an inner perimeter of the disk define a first adhesive free portion of the disk. In some advantageous implementations of the present invention, this first adhesive free portion is dimensioned to prevent the adhesive from extruding beyond the inner perimeter of the disk. In certain advantageous implementations, an outer extent of the adhesive and an outer perimeter of the disk define a second adhesive free portion of the disk. In certain particularly advantageous implementations of the present invention, this second adhesive free portion is dimensioned to prevent the adhesive from extruding beyond the outer perimeter of the disk.